steve_sordy
Wedding Crasher
Over the last two weeks, the 11-speed Shimano shifting on my 2019 Jam2 had become irregular, shifting by itself on gears 5-7 when under load. I kept meaning to look at it... Then yesterday the chain would not stay in the big gear when powering uphill! With the reports on here about emtbs wearing out chains faster I briefly wondering if it could be that, but it didn't feel like chain slip, and I had been checking it. The chief suspect was a bent mech hanger as there was a gouge on the outside of the mech body. I have a mech-hanger alignment gauge and tool, so I resolved to sort that out asap, and today was the day!......
I got the mech hanger alignment tool screwed into the hanger and I noticed that there was movement when there shouldn't be. A quick inspection revealed that the Novatec axle on the rear hub had become loose! The LBS had said not to over tighten; maybe I didn’t get it tight enough before (my torque wrench is broken). The lesson "re-learned" is to check the basics before thinking of anything more exotic!!
The front axle was OK.
Anyway, the hanger alignment was not perfect, but it is now!
While the bike was in the workstand I thought I might as well do a proper job and I removed the chain and reset the whole thing from scratch. The limit screws were both out, B-screw (gap too small), cable tension (slack). I'm surprised the shifting worked as well as it did!
I also checked the chain length and it was OK (0.33% at 575m). That is better than most of my 9 and 10-speed clockwork bikes.
The shifting is now spot on and I'm about to go check it under load.
PS: The chain length on a Large Focus Jam2 is 120 links.
EDIT: 18th Aug'19: The axle came loose again! So I used threadlock and with my new torque wrench, torqued to 14Nm, the max allowable written on the axle. Hopefully that will do the job.
EDIT: 16th Oct'20: It did!
I got the mech hanger alignment tool screwed into the hanger and I noticed that there was movement when there shouldn't be. A quick inspection revealed that the Novatec axle on the rear hub had become loose! The LBS had said not to over tighten; maybe I didn’t get it tight enough before (my torque wrench is broken). The lesson "re-learned" is to check the basics before thinking of anything more exotic!!
The front axle was OK.
Anyway, the hanger alignment was not perfect, but it is now!
While the bike was in the workstand I thought I might as well do a proper job and I removed the chain and reset the whole thing from scratch. The limit screws were both out, B-screw (gap too small), cable tension (slack). I'm surprised the shifting worked as well as it did!
I also checked the chain length and it was OK (0.33% at 575m). That is better than most of my 9 and 10-speed clockwork bikes.
The shifting is now spot on and I'm about to go check it under load.
PS: The chain length on a Large Focus Jam2 is 120 links.
EDIT: 18th Aug'19: The axle came loose again! So I used threadlock and with my new torque wrench, torqued to 14Nm, the max allowable written on the axle. Hopefully that will do the job.
EDIT: 16th Oct'20: It did!
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